3-sided pen



FIG. 1 is a perspective view of a 3-sided pen showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a side elevational view thereof;

FIG. 5 is a side elevational view of the side opposite that shown in FIG. 4;

FIG. 6 is a top end view thereof; and,

FIG. 7 is a bottom end view thereof. 

The ornamental design for a 3-sided pen, as shown and described. 